Pokémon Sapphire Tips

How to get Gyarados?
Capture a Magikarp and raise it to Level 20. Magikarp will evolve into Gyarados. You can also give it to the Lady-Care found in the house in between Verdanturf and Mauville City. If Magikarp is higher than level 20, just make it get to the next level and it will evolve. This is how to get Gyarados instead of trying to make it appear in the wild.